U.S. patent application number 17/245909 was filed with the patent office on 2021-08-12 for surgical cavity drainage and closure system.
The applicant listed for this patent is University of Massachusetts. Invention is credited to Raymond Dunn.
Application Number | 20210244571 17/245909 |
Document ID | / |
Family ID | 1000005553255 |
Filed Date | 2021-08-12 |
United States Patent
Application |
20210244571 |
Kind Code |
A1 |
Dunn; Raymond |
August 12, 2021 |
SURGICAL CAVITY DRAINAGE AND CLOSURE SYSTEM
Abstract
A surgical drain device includes an adhesion matrix of
biodegradable polymer material and a plurality of drain tubes
attached to the matrix. The device is implanted within a surgical
wound to treat the presence of seromas, for example, and is used to
promote drainage, tissue adhesion, and wound closure. The drain
tubes converge into a common collection tube that leads wound fluid
outside the body under gravity feed or negative pressure applied to
the collection tube. The matrix contains an array of apertures that
allow tissue contact across the device. The device also can include
a coating of surgical adhesive and a tissue anchoring system of
hooks or barbs. The device can be used with a negative pressure
system to further improve the drainage band can also be used with a
wound dressing. The device and systems containing the device are
particularly useful to promote the healing of surgical wounds from
abdominal surgery.
Inventors: |
Dunn; Raymond; (Shrewsbury,
MA) |
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Applicant: |
Name |
City |
State |
Country |
Type |
University of Massachusetts |
Boston |
MA |
US |
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Family ID: |
1000005553255 |
Appl. No.: |
17/245909 |
Filed: |
April 30, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15337632 |
Oct 28, 2016 |
11000418 |
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17245909 |
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14111977 |
Oct 15, 2013 |
9597484 |
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PCT/US2012/033608 |
Apr 13, 2012 |
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15337632 |
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61475945 |
Apr 15, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 2027/004 20130101;
A61F 13/00068 20130101; A61M 1/90 20210501; A61F 13/0203 20130101;
A61M 1/0023 20130101; A61M 1/76 20210501; A61F 2013/00412 20130101;
A61F 2013/00174 20130101; A61M 2205/52 20130101; A61M 2205/50
20130101; A61B 17/0401 20130101; A61M 1/84 20210501; A61F
2013/00536 20130101; A61F 2013/0054 20130101; A61F 13/0216
20130101; A61F 13/148 20130101; A61F 13/00072 20130101; A61M 27/00
20130101; A61M 2205/3334 20130101 |
International
Class: |
A61F 13/02 20060101
A61F013/02; A61F 13/00 20060101 A61F013/00; A61F 13/14 20060101
A61F013/14; A61M 1/00 20060101 A61M001/00; A61M 27/00 20060101
A61M027/00; A61B 17/04 20060101 A61B017/04 |
Claims
1. A surgical drain device comprising: a plurality of drain tubes
positioned with an adhesion matrix within a flap wound, the
adhesion matrix having a wound conforming shape and comprising a
plurality of apertures for tissue contact through the matrix, the
drain tubes being configured to be positioned in a spaced apart
distribution within the wound and being removable from the wound
through a single exit site; and an external drain tube connectable
to a negative pressure source, the external drain tube being in
fluid communication with the plurality of drain tubes through the
single exit site.
2. The device of claim 1 wherein the adhesion matrix further
comprises an adhesive.
3. The device of claim 1 wherein the adhesion matrix further
comprises a tissue anchor.
4. The device of claim 1 wherein the plurality of drain tubes
comprises at least three tubes connected to a manifold.
5. The device of claim 4, wherein the manifold is connectable to
the negative pressure source and the drain tubes are positioned in
a spaced array emanating along different radial directions from the
manifold.
6. The device of claim 1 wherein the adhesion matrix comprises a
sheet having a thickness of less than 2 mm.
7. The device of claim 1 wherein the apertures have a total of at
least 50 percent of a total surface area of the matrix and have
varying sizes.
8. A system for surgical wound drainage, the system comprising: the
drain device of claim 1; and a vacuum source, wherein the negative
pressure source comprises the vacuum source.
9. The system of claim 8, further comprising a wound dressing.
10. The system of claim 9, wherein the wound dressing is configured
to overlie a drain tube exit site.
11. The system of claim 8, further comprising a flow regulation
system that regulates flow from the drain tubes.
12. A surgical device to treat or prevent seroma, comprising: a
plurality of at least three drain tubes having distal ends that are
configured to be positioned in a spaced apart distribution within a
partially closed flap wound such that flap tissue contacts opposing
tissue at areas between the plurality of the at least three drain
tubes in the spaced apart distribution, each drain tube including
apertures along a length of the drain tube such that fluid within a
wound can flow through the apertures and into a channel of at least
one of the drain tubes; an external tube connectable to the
plurality of at least three drain tubes and configured to be
positioned at a single exit site through skin of the partially
closed flap wound, the external tube being connectable to a
negative pressure source to facilitate drainage of fluid, wherein
the plurality of at least three drain tubes are removable from the
wound for wound closure.
13. The surgical device of claim 12, further comprising the
negative pressure source connected to the external tube.
14. The surgical device of claim 12, further comprising an adhesion
matrix attached to the plurality of at least three drain tubes that
holds the drain tubes in a fan-shaped distribution.
15. The surgical device of claim 14, wherein the adhesion matrix
further comprises an adhesive configured to attach tissue to the
adhesion matrix.
16. The surgical device of claim 14, wherein the adhesion matrix
further comprises a plurality of tissue contact apertures that
enable tissue growth through the adhesion matrix.
17. The surgical device of claim 12, further comprising a manifold
positionable external to the single exit site that connects the
single external tube to the plurality of drain tubes.
18. The surgical device of claim 12, further comprising a layer
with drain channels between adjacent drain tubes.
19. The surgical device of claim 12, wherein at least one of the
drain tubes comprises a lumen having a closed end.
20. A surgical drain system, comprising: the surgical device of
claim 12; the negative pressure source that further comprises a
pump; a microprocessor connected to the pump and to a flow valve to
control a vacuum level and a rate of fluid removal in the drain
tubes; and a memory to store data including a rate of flow measured
by a flow meter.
21. The surgical device of claim 12, further comprising a dressing
configured to be applied on a surface of the skin around the wound
and overlying the single exit site of the partially closed
wound.
22. A surgical device to treat or prevent seroma, comprising: a
plurality of at least three drain tubes having distal ends that are
configured to be positioned in a spaced apart radial distribution
when positioned within a partially closed flap wound such that flap
tissue contacts opposing tissue at areas between the plurality of
at least three drain tubes in the radial distribution, each drain
tube including apertures along a length of the drain tube such that
fluid within a wound can flow through the apertures and into a
channel within each of the drain tubes; and an external tube
connectable to the plurality of at least three drain tubes with a
manifold and positionable relative to a single exit site through
skin of the partially closed flap wound, the external tube
connectable to a negative pressure source to facilitate drainage of
fluid, wherein the plurality of at least three drain tubes are
removable from the wound for wound closure.
23. The surgical device of claim 22, further comprising a layer
with drain channels between adjacent drain tube.
24. The surgical device of claim 22, further comprising an adhesion
matrix attached to the plurality of at least three drain tubes that
holds the drain tubes in the fan-shaped distribution.
25. The surgical device of claim 24, wherein the adhesion matrix
further comprises an adhesive configured to attach tissue to the
adhesion matrix.
26. The surgical device of claim 24, wherein the adhesion matrix
further comprises a plurality of tissue contact apertures that
enable tissue growth through the adhesion matrix.
27. The surgical device of claim 22, wherein at least one of the
drain tubes comprises a lumen having a closed end.
28. A surgical drain system, comprising: the surgical device of
claim 22; the negative pressure source including a pump, a
microprocessor connected to the pump and to a flow valve to control
a vacuum level and a rate of fluid removal in the drain tubes; and
a memory to store data including a rate of flow measured by a flow
meter.
29. The surgical device of claim 22, further comprising a dressing
configured to be applied on a surface of the skin around the wound
and overlying the single exit site of the partially closed wound.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. Application
divisional of U.S. application Ser. No. 15/337,632, filed Oct. 28,
2016, which is a divisional of U.S. application Ser. No.
14/111,977, filed Oct. 15, 2013 and now U.S. Pat. No. 9,597,484,
which was a 35 U.S.C. .sctn. 371 national stage filing of
International Application No. PCT/US2012/033608, filed Apr. 13,
2012, which claims priority to U.S. Provisional Application No.
61/475,945, filed Apr. 15, 2011. The entire contents of each of the
above applications is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] A variety of systems have been proposed for draining
surgical wounds. The efficacy of such systems has been limited,
however, especially for larger surgical spaces or those in which
certain characteristics, such as motion or shape, or certain
physiological characteristics, such as lymphatic drainage or low
protein exist. Seroma is a frequent complication following surgery,
and can occur when a large number of capillaries have been severed,
allowing plasma to leak from the blood and lymphatic circulation.
Surgical wounds that can lead to seroma formation include wounds
resulting from surgery involving an abdominal flap, such as
abdominoplasty surgery, breast reconstruction surgery,
panniculectomy, and ventral hernia repair.
[0003] Available surgical drain devices suffer from several
deficiencies, particularly when applied following abdominal flap
surgery. They fail to drain fluid adequately, are prone to
clogging, and fail to promote tissue adhesion within the wound.
Thus, there remains a need to develop improved treatments for
surgical wounds. The need is particularly acute in abdominal
surgery, such as for the prevention and treatment of seromas, but
also for any surgical wound predisposed to conditions of excess
fluid drainage or tissue motion, or benefitting from tissue
adhesion needs, such as pressure ulcers or wounds resulting from a
tissue harvesting procedure.
SUMMARY OF THE INVENTION
[0004] The invention provides a surgical drain device for the
prevention and treatment of seromas as well as for general use in
promoting drainage of surgical wounds and wound closure. The drain
device includes a plurality of drain tubes disposed on a substrate
termed an "adhesion matrix," which is designed to promote tissue
adhesion within the seroma or wound space. The adhesion matrix has
a conformable configuration and is made of a compliant material
having planar surfaces that can curve to adapt to the shape of the
wound space.
[0005] In a preferred embodiment, the adhesion matrix contains a
plurality of apertures, or gaps in the matrix material, which allow
tissue contact across the matrix, so as to promote adhesion and
wound closure. Thus, a tissue surface on a first side of the matrix
can directly contact a tissue surface on a second, or opposite,
side of the matrix to promote rapid healing and stabilization of
the wound. The number, size and distribution of the apertures
extending through the matrix can be selected based on the geometry
of the wound. For abdominal wounds, for example, the drain tubes
can be positioned in a fan shaped array with a plurality of three
or more tubes extending from a manifold. The matrix and/or the
tubing can be cut or shaped by the user to conform to the shape of
the wound. The matrix can also be used as a medication carrier to
assist in the administration of a drug to a patient. The matrix can
optionally include a layer of adhesive on at least a portion of any
of its surfaces. The drain tubes can be removed from the device
once drainage flow is sufficiently reduced, and the adhesion matrix
can remain within the body, where it is degraded and absorbed over
time, remaining in place to optimize tissue healing. The matrix can
comprise a porous biodegradable polymer material. As the plurality
of tubes extend from a single exit site into the wound with spaced
apart distal ends, a user can readily remove all the tubes
simultaneously from the wound.
[0006] The surgical drain device can include a tissue anchoring
system, whereby the device is mechanically attached to surrounding
tissues by an array of surface barbs or hooks. These surface
structures can be located on any exposed surface of the adhesion
matrix. When the device is implanted, the surrounding tissues can
be pressed against the barbs or hooks to embed them within the
tissue and anchor the device. The use of surface barbs or hooks can
be used in combination with a surgical adhesive, providing a much
stronger bond between tissue layers than the adhesive alone, and
providing temporary adhesion while the adhesive sets. The structure
of the hooks can have various forms depending on the tissue they
are intended to bind. Longer hooks can be used for loosely bound
tissues such as fat or connective tissue, while shorter hooks can
be used for denser tissues such as muscle. Anchors with more rigid
stems can be utilized to penetrate denser tissues.
[0007] Another aspect of the invention is a system for surgical
wound drainage. The system includes the drain device described
above together with a vacuum source, such as a pump, and a tube
connecting the vacuum source to the drain tubes of the drain
device. The system optionally also can include a fluid trap to
collect drained fluid and a control unit to monitor and control the
application of vacuum and the collection of fluid. Further
components of the system can include a vacuum or pressure gauge, a
flow meter, and a computer to monitor vacuum and flow and to
regulate vacuum or flow.
[0008] Another aspect of the invention is a method for treating or
preventing a seroma, or promoting the drainage or closure of a
surgical wound. The method includes positioning the drain device
described above into a seroma, or a surgical wound, such as a wound
at risk of forming a seroma, and allowing the device to drain fluid
from the wound for a period of time. The device can include
surgical adhesive and/or barbs or hooks on its surface to create
adhesion between tissue layers within the wound and to anchor the
device in place. Drainage can be by gravity flow or can be vacuum
assisted by attaching a vacuum source to the drain tubes of the
device, using a manifold to merge the flow paths of the drain tubes
to a common drain tube for collection. Negative pressure applied to
the drain tubes can be used to hold the tissue layers above and
below the device together until a surgical adhesive has set, or
until the wound healing process binds the tissues together. The
application of negative pressure further facilitates contact
between tissue on opposite sides of the matrix through the
apertures in the matrix to promote tissue adhesion. This improves
the rate of healing while at the same time providing for drainage.
Optionally, the drain tubes of the device can be removed from the
body after drainage flow is reduced, thereby reducing the burden
for resorption by the body. Removal of the drain tubes can be
facilitated by the inclusion of drain tube channels, or drain tube
release tabs, within the adhesion matrix. Release of the drain
tubes is then accomplished by sliding the tubes out of the channels
or appropriately maneuvering the drain tube assembly to break
release tabs. The adhesion matrix is allowed to remain in the
seroma or surgical wound where it is resorbed over time.
[0009] The flow rate from the drain tubes can be regulated by flow
control elements. The flow rate can also be measured or the
pressure of fluids can be measured by ultrasound devices or by
other methods. The system can also be used in conjunction with
wound dressings that can also be attached to a negative pressure
source to remove fluids from the wound.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 shows a drawing of the abdomen of a patient who has
an abdominal flap wound resulting from abdominal surgery.
[0011] FIG. 2 shows a drawing of a surgical drain device according
to the invention which has been inserted through an abdominal flap
wound.
[0012] FIG. 3 shows a cross-sectional view of a surgical drain
device according to the invention installed in the abdomen of a
human patient between subcutaneous tissue and a layer of abdominal
muscle.
[0013] FIG. 4 is a schematic diagram of a surgical wound drainage
system according to the invention.
[0014] FIGS. 5A-5G are illustrations of embodiments of a surgical
drain device according to the invention, depicting the disposition
of drain tubes within the device and features of the drain tubes
and polymer matrix. FIGS. 5A-5D show representative embodiments
having different mechanisms of attaching drain tubes to the polymer
matrix. In FIG. 5A the drain tubes are encased within drain tube
channels, and in FIG. 5B the drain tubes are attached via retaining
structures. In FIG. 5C the drain tubes are glued onto the matrix,
and in FIG. 5D the drain tubes are spot welded onto the matrix.
FIGS. 5E and 5F show embodiments having different configurations of
drain tubes within drain tube channels. FIG. 5G shows a drain tube
embodiment having lateral apertures for collection of fluid.
[0015] FIGS. 6A-C show illustrations of embodiments of an adhesion
matrix having different types of tissue contact apertures. FIG. 6D
is an illustration of an adhesion matrix embodiment possessing
tissue anchors on its surface. FIG. 6E shows a cross-sectional view
of the adhesion matrix of FIG. 6D.
[0016] FIGS. 7A-7C are cross-sectional illustrations of different
embodiments of the drain device positioned within a wound or
seroma. These embodiments include one or more layers of
adhesive.
[0017] FIG. 8 illustrates a process sequence of performing wound
closure treatment in accordance with preferred embodiments of the
invention.
[0018] FIG. 9A illustrates a wound drainage and wound dressing
system in which the wound dressing does not overlie the drainage
exit site.
[0019] FIG. 9B illustrates a wound drainage and dressing system in
which the wound dressing overlies the drainage exit site.
[0020] FIGS. 10A and 10B illustrate cross-sectional view of
drainage exit tube assemblies that can be used in preferred
embodiments of the invention.
[0021] FIG. 11 is a side view of a tissue anchoring mesh in
accordance with preferred embodiments of the invention.
[0022] FIG. 12 is a process flow diagram illustrating a method of
using a wound dressing and drainage system in accordance with
preferred embodiments of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention provides a surgical drain device,
system, and method that allow fluid to be drained from surgical
wounds and promote the healing of the wound. Preferred embodiments
are used to prevent or treat seromas, for example. The drain device
features a set of drain tubes that are attached to a substrate,
herein referred to as an adhesion matrix, that is designed to
promote adhesion of tissues within the wound or seroma and to
encourage cellular infiltration into the device itself. The drain
tubes are distributed across the adhesion matrix to promote even
drainage across the device. To promote optimum drainage, the drain
tubes can be uniformly distributed across the adhesion matrix. The
drainage device can be left in place within the wound for a period
of time, e.g., until fluid seepage diminishes, after which the
drain tubes can be withdrawn from the device and removed from the
patient without disturbing the adhesion matrix, which is left in
place to biodegrade or become incorporated into the healing
process. The device efficiently promotes the healing of even large
area wounds such as those resulting from abdominal flap
surgery.
[0024] A surgical drain device according to the invention is
inserted through an incision in the skin of a patient and placed
within a wound formed during surgery. A first purpose is to drain
fluid during the surgical procedure. The system can be left in
place and to provide drainage for days or even weeks following
surgery. The device can be used for the treatment of a seroma,
e.g., to drain a seroma and thereby promote its healing, it can
also be used to prevent seroma formation. For example, the drain
device can be placed routinely into surgical incision areas
immediately following surgery and used to drain the area and aid in
the prevention of seroma formation. Alternatively, the device can
be placed into a seroma that has already formed by opening the
seroma and installing the device. The use of the drain device is
understood to "prevent" seroma formation even if it merely reduces
the likelihood of seroma formation. Similarly, the use of the drain
device is understood to "treat" seroma formation even if it merely
increases the likelihood that the seroma will heal. FIG. 1 shows an
abdominoplasty or abdominal flap wound (10) in a patient resulting
from abdominal surgery. FIG. 2 shows surgical drain device 20
inserted through abdominal flap wound 10 and into the space
occupied by seroma 15.
[0025] The device according to the invention includes a number of
removable drain tubes 30 attached at their proximal ends to
manifold 40, which connects to a vacuum source through vacuum
tubing 50. The drain device collects and removes fluid from the
abdominal region or from the fluid space of a seroma through the
drain tubes, which divert the fluid outside the patient through the
aid of a vacuum source. The number of drain tubes can vary
depending upon the needs of the device, including the amount of
fluid to be drained and the size of the wound and shape of the
device. Typically, the device will contain from 2 to about 20 drain
tubes. In a preferred embodiment, the device contains preferably at
least 3 tubes, and for larger areas such as the abdomen, for
example, from about 5 to about 12 tubes.
[0026] The drain tubes can be fabricated from any biocompatible
thermoplastic or thermoset material. Examples include surgical
grade silicone rubber, polyurethane, polyamide, polyimide, PEEK
(polyether ether ketone), polycarbonate, PMMA
(polymethylmethacrylate), and polyvinylchloride. The drain tubes
are intended to be removed after fluid build-up has reduced to a
level that is stable without drainage. However, in an alternative
embodiment, the drain tubes can be made of a biodegradable material
and can be left in place. The drain tubes can be flexible so as to
conform to the tissues surrounding the device and to accommodate
movement of the patient without causing discomfort. The drain tubes
can be open ended or close ended. In a preferred embodiment, the
drain tubes are close ended and possess apertures or holes along
their length for the uptake of fluid.
[0027] FIG. 3 shows drain device 20 installed in the abdomen
between subcutaneous tissue 70 and a layer of abdominal muscle 80
and associated fascia 90. While this position can be used following
abdominal flap surgery, other anatomical locations of the device
are also possible and are contemplated as suitable uses of the
invention.
[0028] FIG. 4 schematically depicts a system for drainage of a
seroma through an abdominal flap wound. System 21 includes drain
device 20, having a plurality of drain tubes 30 attached to
adhesion matrix 25 and configured so as to drain the full extent of
the seroma. The drain tubes are connected at their proximal ends to
manifold 40, which is in turn connected through vacuum tubing 50 to
a vacuum pump 130 or other vacuum source. Fluid 125 drained from
the wound can be optionally accumulated in fluid trap 120. Vacuum
pump or other vacuum source 130 can include one or more electronic
devices, such as a microprocessor with memory and software, to
monitor the vacuum level, pneumatic resistance, and/or fluid
removal amount or rate. The electronic device(s) also can be used
to control the operation of the system over time according to
user-defined parameters, according to a preset program, or in
response to data collected on vacuum, resistance, and/or fluid
removal.
[0029] FIGS. 5A-5G depict representative embodiments of a drain
device according to the invention, showing several possible
configurations of the drain tubes within the device. FIG. 5A shows
an embodiment in which each drain tube 30 is disposed within a
separate drain tube channel 35. The drain tube channels are
embedded within or attached to the surface of adhesion matrix 25
and determine the orientation and distribution of the drain tubes
within the device. In a preferred embodiment, the drain tube
channels, and consequently the drain tubes, are evenly distributed
across the surface area of the drain device, as shown in FIG. 4.
These can extend in a generally radial distribution from one edge
or region on the matrix to enable use of a single exit tube from
the wound. However, the drain tubes can be unevenly distributed if
desired, e.g., to increase the drainage capacity or rate from
specific areas of the device. The use of drain tube channels
ensures that the drain tubes remain in position within the patient
and ensures that the drain tubes can be removed easily at the
appropriate time, without disrupting the wound healing process.
Drain tube channels require a mechanism to accept fluid and pass it
on to the drain tubes within. Suitable mechanisms include using
apertures or holes of any desired shape and distribution along the
length of the channels (see, e.g., apertures 33 on channels 35 in
FIG. 6D), and using a porous material to form the drain tube
channels (see drain tube channels 35 in FIGS. 5E and 5F,
constructed of a porous polymer matrix).
[0030] Several alternative embodiments are also contemplated which
lack drain tube channels. FIG. 5B depicts the use of retaining
structures 35a instead of channels in order to removably attach the
drain tubes to the adhesion matrix, while allowing removal of the
tubes by sliding or by breaking off the retaining structures. The
retaining structures can have any form compatible with their
function. FIG. 5C shows an embodiment in which drain tube 20 is
held in place by layer of adhesive 31, and the tube is fitted
within a depression on the surface of adhesion matrix 25. In the
related embodiment shown in FIG. 5D, the drain tube is held in the
matrix depression by spot welds or adhesion points 32, which can be
broken through suitable manipulation to remove the tubes.
[0031] FIGS. 5E and 5F present cross-sectional views of a portion
of the adhesion matrix 25 of an embodiment of a drain device
according to the invention. The adhesion matrix contains regions
for receiving drain tubes or can include one or more drain tube
channels 35 which surrounds drain tubes 30, having lumen 34,
through which seroma or other wound fluid is removed. A round Blake
drain is depicted as the drain tube in FIG. 5E, and a flattened
version in FIG. 5F. A variety of drain tube profile shapes are
possible, including oval, elliptical, square, rectangular,
triangular, flattened, compound (i.e., having 2 or more parallel
lumens, interconnected or separated), or irregular. The drain tubes
optionally can be coated with a lubricant on their outer surfaces
to facilitate their removal from the channels.
[0032] In a preferred embodiment the drain tubes possess openings
or apertures 33 along their length to permit fluid to enter for
drainage. FIG. 5G depicts one such embodiment. The relative surface
area and distribution of such apertures can be chosen so as to
regulate flow through the drain tubes. For example, pressure drop
(i.e., loss of vacuum) along the length of the drain tubes can be
compensated by increasing the open surface area or the density of
apertures towards the distal end of the drain tubes. Drain tubes
are preferred which have an aperture distribution that provides an
essentially constant rate of fluid uptake along the length of the
drain tubes (e.g., increasing aperture area towards the distal
end), so that uniform drainage is obtained across the drain
device.
[0033] Adhesion matrix 25 includes a plurality or matrix of
apertures 27 which allow tissue contact through the drain device.
Such tissue contact promotes wound healing and the sealing of
capillaries, which is important for treating seromas or preventing
their formation. In the drain device according to the present
invention, the promotion of tissue contact works in combination
with fluid drainage to promote wound healing. The adhesion matrix
25 and its drain tube channels 35 preferably are constructed of one
or more biodegradable polymer materials and can be left within the
wound, where they stabilize tissue infiltration and adhesion and
thus promote the healing process. The size, shape, and distribution
of the tissue contact apertures 27 can be varied according to
individual needs. However, greater tissue contact across the device
will promote better adhesion, drainage, and wound closure.
Therefore, it is preferred that at least about 50%, 60%, or 70%,
and preferably about 75-80% of the total surface area (one side) of
the drain device remains open in the form of tissue contact
apertures. The distribution and spacing of tissue contact apertures
can be varied as desired, and the apertures can be the same,
similar, or different in shape, size, and distribution across the
device. For example, the apertures can be distributed with an
average center-to-center spacing in the range of about 2 mm to
about 20 mm or more, and the average individual aperture surface
area can be in the range from about 1 mm.sup.2 to about 5 cm.sup.2.
In a preferred embodiment, the apertures have about 1 cm.sup.2
average surface area, and their number or their collective surface
area become progressively larger from the proximal end of the drain
device (i.e., near the exit point from the body) toward the distal
end of the device (deep within the wound or seroma), so that tissue
adhesion and wound closure progress from deep within the wound
towards the surface of the body.
[0034] FIGS. 6A-E show several embodiments of the adhesion matrix.
A portion of the adhesion matrix 25 between two neighboring drain
tubes 30 and drain channels 35 is shown. The embodiment shown in
FIG. 6A has a regular arrangement of rectangular apertures 27 to
allow tissue contact through the device. Circular apertures are
shown in FIG. 6B. The embodiment of FIG. 6C includes apertures 27
that are formed into lateral channels. Fluid flows laterally
through these channels toward openings 36 in the drain tube
channels, drawn by the reduced pressure in the drain tubes. As
shown in FIGS. 6D and 6E, the surfaces of the adhesion matrix,
including the drain channels, can be endowed with an array of hooks
or barbs to promote anchoring of the device to adjacent tissues. In
the embodiment shown in FIG. 6E, the hooks on the upper side 28 are
longer than the hooks on the lower side 29. This arrangement can be
used where the tissues on either side of the device are of
different density. For example, longer hooks such as about 1.5 to
about 3 mm in length are preferred for less dense tissue, such as
subcutaneous fat tissue, whereas shorter hooks such as about 0.5 to
about 1.5 mm in length are preferred for denser tissues such as
fascia and muscle.
[0035] The adhesion matrix, including any drain tube channels and
hooks or barbs, can be fabricated from a biodegradable polymer
material, as these structures are intended to remain in place in
the patient's body after removal of the drain tubes, so as not to
disrupt the healing process. Examples of suitable biodegradable or
resorbable materials include Vicryl (polyglycolic acid), Monocryl
(glycolic acid- -caprolactone copolymer), PDS (polydioxanone, PDO),
PLA (polylactic acid, polylactide), PLLA (poly-L-lactic acid), PDLA
(poly-D-lactic acid), PGA (polyglycolic acid, polyglycolide), PLGA
(poly(lactic-co-glycolic acid)), PHB (polyhydroxybutyrate), and PCL
(polycaprolactone). In a preferred embodiment, the adhesion matrix,
including any drain tube channels, is formed of an open network of
polymer chains that has sufficient porosity to allow infiltration
by cells and fluid flow across the material. Cellular infiltration
can promote tissue adhesion and the biodegradation of the polymer
after the wound has healed. In some embodiments, the adhesion
matrix including any drain tube channels is permeable to seroma
fluid but not permeable to cells. In other embodiments, the
adhesion matrix, including any drain tube channels, is permeable to
fluid and electrolytes but is impermeable to proteins. The
permeability properties of the matrix polymer material that makes
up the basic substrate of the matrix can be the same or different
compared to the material that makes up the drain tube channels. In
a preferred embodiment, the polymer chains, or fibers composed of
polymer chains, of the adhesion matrix are aligned along an axis
substantially perpendicular to the axes of the nearest drain tubes.
This alignment pattern promotes the flow of fluid through or along
the surface of the adhesion matrix towards the drain tubes.
[0036] The adhesion matrix, and thus the overall drain device, can
have any form suitable for insertion into the wound or seroma where
it is to be inserted. Generally, the form is that of a thin sheet
having an essentially rectangular shape. However, the shape can be
rounded, circular, elliptical, oval, or irregular. Preferably the
corners are rounded so as to minimize mechanical irritation of
surrounding tissues. The size of the device is also determined by
the particular use and anatomy of the patient. For example, the
adhesion matrix can have an overall width and length in the range
from about 2 cm to 25 cm, such as about 10 cm.times.12 cm or about
20 cm.times.25 cm. The thickness of the adhesion matrix can be from
about 0.5 mm to about 1 cm; where the sheet of material is
preferably less than 5 mm in thickness and preferably the adhesion
matrix is about 1-2 mm thick. The thickness of the entire drain
device, including the sheet of the adhesion matrix, drain tubes,
and any hooks or glue pads is about 5 mm or less, 10 mm or less, or
about 5-10 mm.
[0037] The adhesion matrix can be coated with an adhesive material
such as a surgical glue either in addition to or instead of using
hook or barb structures that stabilize tissue layers on either side
of the drain device. Any type of surgical adhesive suitable for use
within the body can be used, including polyethylene glycol
polymers, adhesive proteins, gelatin-thrombin mixtures,
albumin-glutaraldehyde, and fibrin-based sealants. Cyanoacrylates
are to be avoided, as they cause inflammation if used internally.
An adhesive coating can be placed on one or both surfaces of the
adhesion matrix. Adhesive coatings can be applied to the device
prior to its placement in a patient, i.e., as part of the device
fabrication process. An adhesive coating can cover all or a portion
of a surface of the device. A surgical adhesive can be used in the
form of a fibrous mat or pad that is soaked with an adhesive
composition. The mat or pad is preferably fabricated from a
biodegradable polymer, such as the type used to prepare the
adhesion matrix. One or more layers of adhesive material can be
placed between the device and surrounding tissue at the time of
placement in the patient. FIGS. 7A-7C illustrate the placement of
supplemental adhesive layers with the drainage device. In FIG. 7A,
adhesive layer or pad 140 has been placed into a wound or seroma
adjacent to exposed tissue 150. In FIG. 7B, drainage device 20 has
been placed onto the adhesive layer as shown in FIG. 7A, and the
wound then closed and vacuum applied, so that the device-adhesive
pad sandwich is surrounded by tissue 150. FIG. 7C depicts the
structure obtained if a second adhesive pad or layer 140 is added
adjacent to the drainage device on the opposite side of the first
adhesive layer.
[0038] The invention also provides a method for treating or
preventing a seroma as illustrated in FIG. 8. The method also can
be used to promote wound closure after surgery 210, to prevent
infection after surgery, and to improve the strength and/or
cosmetic appearance of a surgical wound after it has fully healed.
A drain device according to the invention is positioned into a
surgical wound 220, such as a wound following abdominal flap
surgery. The device has been sterilized prior to placement within
the wound. Optionally, one or more layers of surgical adhesive is
placed on one or both sides of the device, interfacing between the
device and surrounding tissue 230. If the device includes hooks or
barbs on one or both sides, pressure is applied to the surface of
the device in order to set the hooks or barbs into the surrounding
tissue. The wound is then partially surgically closed at the
surface, leaving a single tube exiting the wound. The tube is then
attached to a vacuum source 240, and vacuum is applied 250 so as to
initiate drainage through the device. The rate of drainage is
controlled by the level of vacuum applied. The amount of vacuum is
sufficient to promote drainage without causing damage to the
tissues surrounding the implanted device. For example, the vacuum
can be in the range from about 75 to 250 mm Hg. After the rate of
fluid drainage has decreased to acceptable levels, the vacuum is
removed and the drain tubes are removed 260 by slowly pulling them
out through the remaining wound opening, which is subsequently
closed. The adhesion matrix remains in the patient and is
biodegraded and absorbed over a period of weeks to months.
[0039] Illustrated in connection with FIGS. 9A and 9B are uses of a
wound dressing in combination with the adhesion matrix or mesh
device and a negative pressure drainage system. After placement of
the matrix 404, as described in detail herein, the drainage tubing
405 extends through an exit site 409 of the skin 401 of a patient.
The wound can frequently require the use of a wound dressing 402
that is placed externally on the skin of a patient. The wound
dressing can either overlie the exit site 456 as shown in FIG. 9B,
or the wound dressing can be placed laterally (or non-overlying)
from the exit site 409 as shown in FIG. 9A. The tubing 405 can
either connect directly to the pump 420, or can utilize a connector
or manifold 412 positioned on or above the skin 401, which can be
connected to the pump 420. A valve 408 can be used to control the
application of negative pressure. A flow meter can be included at
the connector or manifold 412 or at the valve 408 to measure the
fluid removal rate and total amount of fluid removed. A
quantitative measure of the fluid removed can thereby be measured
and recorded. Other diagnostic measurement devices, such as
ultrasound, can also be used to measure the amount and location of
fluid or seromas within the wound. This information can be used to
adjust the amount and distribution of negative pressure applied
within both the wound using drainage system 404, 454 and the wound
dressing 402, 452.
[0040] Negative pressure can be applied to the wound dressing 402
through separate tube 415 that can be attached to the same pump 420
as the drainage system or a second pump. A valve 406 can be used to
regulate pressure to the wound dressing. In the embodiment of FIG.
9B, tube or tubes 458 can exit the wound and attach at connector
462 to the underside of the dressing 452. A manifold 470 can
control the distribution of negative pressure to both the dressing
452 and the drainage device 454 using passive or active flow
control elements. The manifold can be attached using a single tube
460 to pump 480. The pump 420, 480 can be operated by hand or
electronically. The pump can have internal electronic control,
memory and display features 485 to control system operation and
record patient data.
[0041] Shown in FIGS. 10A and 10B are preferred embodiments of
drainage tube assemblies that can be used in conjunction with the
invention. The drainage tubing 405, 458 preferably exits the wound
as a single tube or as a cluster of tubes within an outer tube. The
outer tube 504 can either be a flattened shape 500 of a plurality
of three or more tubes 502 arranged in line as shown in FIG. 10A,
or can be circular 520 with drainage tubes 522 extending within
outer tubes 522 to the pump or connector. In certain applications,
it may be advantageous to remove the tubes separately at different
times from the drainage system as certain regions may drain more
quickly. However, for many wounds it is useful to simultaneously
remove all drainage tubes from the wound.
[0042] Shown in FIG. 11 is a side view of an adhesion matrix or
mesh 540 used in preferred embodiments of the invention. It can
frequently be useful to employ such a mesh to facilitate wound
adhesion and healing using an absorbable material that can adhere
on both sides to tissues within a wound. Frequently, these tissue
are of different types on opposite sides of the mesh. Thus, the
mesh can include a conformable layer 542 having tissue anchors 544,
546 on both sides. However, as one side may be used to attach to
the fatty or adipose tissue on the underside of a flap of skin, the
first plurality of tissue anchors 544 has a shape and rigidity
suitable for attaching to adipose tissue. The second plurality of
tissue anchors can be shaped and sized to attach to less compliant
tissues such as fascia or muscle. More rigid hooks or barbs are
needed to enable this attachment.
[0043] Shown in FIG. 12 is a sequence of steps in a method 600 of
applying a drainage and wound dressing system in accordance with
the invention. After performing a procedure 610 on a patient, a
wound closure device is inserted 620 into the wound of a patient.
This can be a combination of elements, such as meshes as shown in
FIG. 11 in certain regions of the wound, and a drainage and mesh
system as described generally herein in regions of the wound
requiring drainage of fluid. This can also include the user 630 of
adhesives and/or tissue anchors to enable more direct contact of
tissues through the mesh and thereby improve the rate of healing. A
wound dressing can also be applied 640 to the wound as described
herein. A pump can then be attached 650 to the drainage system
and/or the wound dressing and a negative pressure can be applied
660 to one or both elements to drain fluid and promote contact
between tissues through the implanted mesh or matrix. The flow rate
of fluid through each tube can be measured and recorded and the
presence of fluid can be monitored 670 by ultrasound or other
systems. The drainage tubing can be removed 680 when the drainage
rate diminishes. The wound dressing can be replaced 690 as needed
and can continue to be used to drain 690 the wound.
[0044] While this invention has been particularly shown and
described with references to preferred embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and/or details therein and equivalents thereof may be made
without departing from the spirit and scope of the invention as set
forth by the appended claims.
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